Growth Dynamics and Decorative Value Easy Pot Potted Freesia Depending on the Growing Conditions Ludmila Startek Agricultural University Department Ornamental Plants Szczecin Poland Tel: 0048-91-4220851**354 Fax 0048-91-4232417 e-mail: kro@ns.rektor.ar.szczecin.pl Keywords: potted freesia, corms, dormancy, storage, fertilization Abstract Comparative studies on four cultivars potted freesia: Pinokkio, Popey, Smarty and Suzy were conducted in the years 1997-98. From January to June freesias were grown in a greenhouse and after the harvest the corms were stored from 5 to 11 months at the temperatures: 0.5-3º C, 14-18º C and 28-30º C. Five corms were planted in a pot into neutralised sphagnum peat. The following fertilization methods were applied: 1. slow-release fertilizer Osmocote Plus 5-6 before planting; 2. popular, traditional fertilizer, Azoska before planting; 3. liquid fertilizer Multivit Plus top-dressing; 4. no fertilizer. Corm preparation before planting was found to have the greatest effect on the growth and development the plants. The best results were obtained when the corms were stored 12-14 weeks before planting at the temperature 28-30º C. The plants fertilised with Osmocote Plus at the dose 5g /dm 3 had the most abundant flowering Popey and Suzy turned out to be the most effective cultivars. INTRODUCTION The Easy Pot dwarf freesia developed by Dutch firm Van Staaveren in the late 90 s enlarged the number potted decorative plants grown commercially. Earlier, there had been some attempts to grow cut-flower freesias as potted plants by inhibiting their growth using retardants and low temperatures [Gianfagna and Wulster (1986) Brondom (1989) Wulster (1989) Berghoef and Zevenbergen (1990a) Hertogh and Milks (1990) Thomas et al. (1998)]. According to the breeder the Easy Pot freesia does not require any special follow-up care. In Poland freesia as a cut flower is one the most popular and appreciated decorative plants whereas potted freesia is a new plant and has not been grown commercially. The aim the present studies was to evaluate the effects the storage temperature the corms on the further freesia development as well as the affects corm size and fertilization on the quality and decorative value potted freesia. MATERIALS AND METHODS In the years 1997-98 the experiment on four cultivars potted freesia Pinokkio Popey Smarty Suzy was conducted. Freesia corms with easily felt apical buds were obtained from the Van Staaveren firm at the beginning January 1997. They were planted in 13-cm pots, 5 corms per pot and cultivated following the breeder s instructions. The plants flowered at the end March and the beginning April and at the end May the leaves started yellowing and drying out. In the middle June the corms with foliage were lifted and left at the temperature 20 to 25ºC to dry for 4 weeks. After that they were cleaned and sorted out for further studies according to their size: to 3.5 cm in circumference and over 3.5 cm. Since the middle July 40 corms each cultivar in two Proc. 8th Int. Symp. on Flowerbulbs Eds. G. Littlejohn et al. Acta Hort. 570, ISHS 2002 385
sizes (altogether 320) were stored in a storeroom at the temperature14-18ºc and remaining corms (1280) in a coolhouse at the temperature 0.5-3ºC. In December the first experiment was set up on 320 corms stored at the temperature 0.5-3ºC and on 320 corms stored at the temperature14-18ºc. At the end January the remaining corms were divided into three groups: 640 corms were placed at the temperature 28-30ºC, 160 at 14-18ºC and the other 160 were left in a coolhouse. At the beginning May when the corms stored for 14 weeks at the temperature 28-30ºC had easily felt buds and roots, they were taken to the storeroom with the temperature 14-18ºC for 10 days and then experiment II was set up. Both the experiments had a similar design. Each object consisted 20 corms and each replication 5 corms planted in 13-cm pots (vol. 0.75dm 3 ). Experiment I Two kinds potting media were used: A sphagnum peat, neutralised (to ph 6.5) with limestone and dolomite at the ratio 2:1; B sphagnum peat neutralised in the same way but enriched with 5g Osmocote Plus 5-6 months per dm 3 applied at planting. In experiment I 32 objects were compared, 16 each time for two kinds corm storage. The effects 3 factors: cultivar (4), corm size (2), the potting medium (2) on the emergence and plant development were examined. Experiment II For the corms stored at 0.5-3ºC and 14-18ºC, only one potting medium was used: neutralised sphagnum peat with 5g Osmocote Plus 5-6. The effects two factors: cultivar (4) and the corm size (2) were studied. The corms stored at the temperature 28-30ºC were planted in neutralised (ph 6.5) sphagnum peat and four fertilization treatments were applied: A no fertilization, B 5g Osmocote Plus 5-6 months per dm 3 at planting, C Azoska 2g/dm 3 two days before planting; D Multivit Plus top dressing, at the concentration 0.5%, 50 ml a week per pot. Chemical composition peat and fertilizer was as follows: Sphagnum peat (mg/dm 3 ): N (NO 3 ) 15; P 54; K 10; Ca 127; Mg - 44; Cl 52. Osmocote Plus 5-6 months (%): N 15;. P 2 O 5 10; K 2 O 12; MgO 2; Fe 0,4; Mn 0,06; Cu 0,05; B 0,02; Mo 0,02; Zn 0,015. Azoska (%): N 13,6;. P 2 O 5 6,4; K 2 O 19,1; MgO 4,5; Fe 0,27; Mn 0,045; Cu 0,18; B 0,045; Mo 0,082; Zn 0,045. Multivit Plus (g/dm 3 ): N 45;. P 2 O 5 30; K 2 O 78; MgO 20; (mg/dm 3 ): Fe 1500; Mn 240; Cu 120; B 180; Mo 20; Zn 120. In experiment I the temperatures ranged from 10-20 0 C, in experiment II from 16-30ºC. There was no artificial lighting in winter and cooling in summer. All the protective measures followed the recommendations for freesia grown as cut flowers. Throughout the experiments there were neither any symptoms leaf necrosis, deformation nor inflorescence discoloration. The evaluation morphological characteristics the plants from experiment I is demonstrated in Table 1. and from experiment II in Table 2. The results the measurements the length and shoot number at full vegetative stage; and the length and the number inflorescences as well as the number flowers at full generative stage were verified statistically by analysis variance for factorial experiments and evaluated by the Tukey test at 0.05. RESULTS AND DISCUSSION Experiment I Freesia corms, placed after harvest at the temperature 14-18ºC, after 5 months storage had well formed, felt buds and roots. Some them, Smarty cultivar in particular, had 1.5-cm long shoots at planting. After planting into the pots, in the greenhouse, at the temperature 12-16ºC freesias emerged soon in 2-7 days. Smarty cultivar emerged first, then in turn Suzy Popey and Pinokkio During vegetation the 386
plants differed in the growth rate but the differences were within 20% and the sequence cultivars according to the value that feature was changing. Bigger corms emerged sooner and more evenly whereas the plants from smaller corms had later vegetation and longer shoots (Table 1). Irrespective the cultivar and corm size the freesias from the medium with Osmocote Plus 5-6 had wider and greener leaves and more upright conformation and 1-2 weeks later started yellowing and dying out. However, the freesia plants obtained in this experiment had no decorative value because they did not flower, produced vegetative parts only. Freesia corms stored at the temperature 0.5-3ºC looked the same after being taken from the cool-house as just after lifting and planted in pots in the greenhouse did not emerge irrespective potting media and did not produce any roots. In the course the experiment i.e. in half a year, they only transformed. One to three corms developed from mother corm and the total corm weight decreased by c.a. 15-20%. Experiment II Freesia corms stored 6 months at the temperature 0.5-3ºC, 3.5 months at the temperature 28-30ºC, and then 10 days at temperature 14-18ºC emerged very soon, after 2-3 days and irrespective the cultivar and the size corms developed dynamically. All the cultivars began flowering 9 weeks after planting. Flowering lasted on the average three weeks. The plants looked very attractive thanks to flowers in all the shades yellow from cream in Suzy to intensive orange in Popey and luscious green leaves. All varieties had a very nice scent. Popey produced most buds, inflorescences and flowers. Differentiated fertilization affected morphological features (Table 2). The best results were obtained in the combinations with Osmocote Plus and in turn with Azoska, Multivit Plus and the poorest without any fertilization. In all the cultivars the kind fertilization affected most the number flowers and inflorescences: on the average in combinations with Osmocote Plus the plants had twice as many flowers than the plants without fertilization. Popey turned out to have the weakest response to fertilization and Pinokkio the strongest (Table 2). Suzy was found to have relatively fewest inflorescences but the greatest number flowers). When it was fertilised with Osmocote Plus 5-6 its inflorescences were the longest and consisted 7 flowers whereas in other cultivars only 3-6 flowers. In all the cultivars larger corms produced the plants with more abundant flowering (by 40% more flowers on the average) and greater number flowers than smaller corms. The size corms was not proved to have any effect on the plant height and length inflorescences (Table 2). The corms stored for 6 months at the temperature 0.5-3ºC and 3.5 months at the temperature 14-18ºC emerged 14 weeks after planting and first flowers appeared 11 weeks later i.e. 25 weeks after planting. There were about 2-5 times fewer flowers than on the plants from prepared corms and they had low decorative value because deformities and discoloration. Therefore, the number flowers and inflorescences were not submitted to statistical analysis. The plants all the cultivars formed by 24-40% fewer shoots and had poorer foliage in comparison with plants obtained from the corms stored at the temperature 28-30ºC. Temperature had no effect on the height plants and the length inflorescences. The corms stored 9.5 months at the temperature 0.5-3ºC transformed after planting as in experiment I and the first uneven emergence was observed after 4-5 months. DISCUSSION Temperature and fertilization are very important factors in production bulbous and tuberous plants. The results the studies on freesia as a cut flower prove that the temperatures at the preparation period corms for further cultivation to a great extent determine the plant development. The results obtained in both the experiments for freesia corms stored at the temperature 0.5-3ºC prove that such temperatures caused very deep corm dormancy which was interrupted by treating the corms with high temperatures, 28-30ºC. This 387
treatment is recommended as an effective method stopping dormancy and accelerating the growth and flowering freesia grown as a cut flower (Berghoef et al. 1986a; Berghoef et al. 1986b; Berghoef and Zevenbergen. 1990b; De Hertogh and Le Nard 1993; Lee- et al 1998). Easy Pot freesias appeared to respond to the storage corms at the temperature 28-30C similarly to the freesia grown as a cut flower, and storing their corms for 7-14 days after preparation at the temperature approximately 16ºC accelerates their flowering. Our results show (Startek et al. in print) that the corms the same cultivars Easy Pot freesia prepared simultaneously under the same conditions, emerged 2-4 days longer and flowered a week later when they had been planted directly after preparation. The corms treated with the temperature 14-18ºC after the harvest produced sprouts 4.5 months later and could no longer be stored. The plants from these corms in experiment I conducted in winter did not flower at all. In experiment II carried out in spring and summer, the corms, stored at the beginning at 0.5-3ºC and then 14-18ºC emerged 14 weeks after planting, flowered 15 weeks later than the plants from the temperature 28-30ºC, they had few flowers bad quality. Van Staaveren (Anonymous 1999) Easy Pot freesia breeder recommends maintaining relatively low temperature, day 10-12ºC, night 6-8ºC. Although in experiment II May July, the temperatures were within 18-30ºC the plants produced flowers after 9 weeks and had very abundant flowering, especially those fertilised with Osmocote Plus 5-6. Thus, it can be supposed that Easy Pot freesias are resistant to high temperature the medium and are similar to the Rapid cultivars freesia, the same breeder, cultivated as cut flowers. It seems likely that low temperatures, recommended by the breeder aim at maintaining compact plant conformation. However, fertilization turned out to affect the quality flowering more than the corm size. Irrespective the cultivar and the size mother corms the freesias without fertilization had the poorest flowering whereas those fertilised either with Osmocote Plus 5-6,Azoska or Multivit Plus had by 160-30% more flowers. Statistical verification the results concerning the effects fertilization on morphological characteristics and flowering confirmed that the best quality flowers were obtained using Osmocote Plus 5-6, - a slow-release fertilizer. One dose 5g fertilizer per dm 3 neutralised peat applied at planting was sufficient for abundant flowering and good plant condition during the whole vegetation period. The breeder also recommends a slow-release fertilizer Osmocote 14-14-14. In Our experiment the effects differentiated doses Osmocote Plus 5-6 were not examined. It may be possible that a higher dose would be more favourable for the plant quality. Thomas et al. (1998) also think that freesia cultivated in containers has relatively high nutritional requirements. CONCLUSION 1. Easy Pot potted freesias show a strong response to the temperature during the storage corms. As in the case freesia cultivated as cut flowers the temperatures at which the corms are stored between harvest and planting have significant effect on emergence, further development and flowering potted freesia. 2. Cultivars: Pinokkio, Popey, Smarty and Suzy flower abundantly and at an appropriate time when their corms are stored at the temperature 28-30ºC for 14 weeks and also when they are cultivated at higher temperatures than recommended by the breeder. 3. The size mother corms affects morphological characteristics plants. Larger corms produce the plants higher quality with more abundant flowering than smaller corms. 4. During cultivation it is necessary to provide potted freesia with appropriate amount nutrients. Good results are obtained using a slow-release fertilizer Osmocote Plus 5-6. Literature cited Anonymous, 1999. Let s talk about easy pot. Van Staaveren, Aalsmeer, Holland. Berghoef, J., Melcherts, J., Mourits, J.W.F. and Zevenbergen, A.P. 1986a. Effect temperature on initiation and development Freesia flowers. Acta Hort. 177:636. 388
Berghoef, J, Zevenbergen, A.P. and Imanishi, H. 1986b. The effect temperature and ethylene on dormancy Freesia corms. Acta Hort. 177, II:631-635. Berghoef, J. and Zevenbergen, A.P. 1990a. The effect precooling, environmental factors and growth regulating substances on plant height freesia as potplant. Acta Hort, 266:115-122. Berghoef, J. and Zevenbergen, A.P. 1990b. The effect air and soil temperature on assimilate partitioning and flower bud initiation freesia. Acta Hort. 266:169-176. Brondom, J.J. 1989. Freesias in pots. Gartner Tidende, Denmark, 105:33, 809-811. De Hertogh, A.A. and Le Nard, M. 1993. The Physiology Flower Bulbs. A comprehensive treatise on the physiology and utilization ornamental flowering bulbous and tuberous plants. Freesia. 21:285-296. Elsevier / Amsterdam, London, New York, Tokyo. De Hertogh, A.A. and Milks, R. 1990. Forcing Dutch grown freesias as potted plants in the U.S. and Canada. Acta Hort. 266:251-257. Gianfagna, T.J. and Wulster, G.J. 1986. Growth retardants as an aid to adapting freesia to pot culture. HortScience, USA, 21 (2):263-264 Lee, J.J., Jeong, J.S. and Kim, J.C. 1998. Effects high-temperature storage and ethylene on breaking dormancy freesia corms, Journal the Korean Society for- Horticultural Science, 39:6, 789-793. Startek, L. Zurawik, P. Rejent, J. and Dobrowolska, A. The influence temperature and storage period corms on the development potted freesia. Zeszyty Naukowe Instytutu Sadownictwa i Kwiaciarstwa w Skierniewicach. In print. Thomas, M., Matheson, S. and Spurway, M, 1998. Nutrition container-grown freesias, Journal--Plant-Nutrition, New Zealand, 21:12, 2485-2496. Wulster, G.J. 1989. The effects greenhouse temperature and ancymidol concentration on height and flowering time Freesia hybrida grown as container plant. Acta Hort. 252:97-103. Tables Table 1. Effects cultivar and size mother corms and fertilization on the morphological traits potted freesia experiment I Trait Cultivars (A) Size corms (B) Fertilization (C) Pinokkio Popey Smarty Suzy >3,5 cm <3,5 cm Osmocote Length stems (cm) Plus Without fertilization 40,6 48,5 42,5 44,7 40,7 47,5 44,5 43,7 LSD 0,05 A 1,84 B 2,65 C n.s.(no significant) stems 3,07 3,81 5,87 3,94 4,03 5,37 4,44 3,90 LSD 0,05 A 0,53 B 0,67 C 0,36. 389
Table 2. Effects fertilization, cultivar and size mother corms on blooming potted freesia experiment II Trait stems Length stems Length inflorescences inflorescences flowers (Cultivar) (A) Osmocote Plus Fertilization (B) Size corms (C) Mean Azoska Multivit Without > 3,5 cm <3,5 cm Plus fertiliza -tion.* Pinokkio Popey 16,00 18,25 13,50 16,25 13,00 13,50 14,25 13,50 15,50 17,88 12,88 12,88 14,19 15,38 Smarty 14,50 13,00 11,50 11,50 15,25 10,00 12,63 Suzy 8,75 11,75 9,00 7,75 10,88 7,75 9,31 Mean 14,38 13,63 11,75 11,75 14,88 10,88 LSD 0,05 A - 3,09 B - 1,96 C - 1,27 A(B) - 4,20 B(A) - 3,32 A(C) 3,51 C(A) - 1,54 Pinokkio 35,85 32,63 29,88 32,62 33,06 32,43 32,74 Popey 36,13 34,00 30,93 30,78 32,05 33,86 32,96 Smarty 33,85 34,83 25,88 19,60 28,94 28,14 28,54 Suzy 38,88 37,15 33,40 34,03 34,54 37,19 35,86 Mean 36,18 34,65 30,02 29,26 32,15 32,90 LSD 0,05 A - 1,08 B - 2,19 C n.s. A(B) - 3,85 B(A) - 4,38 A(C) - 4,34 C(A) - 1,23 Pinokkio 31,38 27,88 23,25 25,75 28,50 25,63 27,06 Popey 30,25 31,00 30,75 31,75 3125 30,63 30,94 Smarty 25,75 31,75 27,75 27,00 28,75 27,38 28,06 Suzy 33,75 33,38 31,50 31,75 32,00 33,19 32,59 Mean 30,28 31,00 28,31 29,06 30,13 29,20 LSD 0,05 A - 4,69 B = 1,53 C - n.s. A(B) - 3,91 B(A) - 3,05 A(C) - 3,20 C(A) - 2,29 Pinokkio Popey 9,75 12,00 6,00 11,75 6,75 10,75 3,50 9,00 8,63 12,00 4,38 9,75 6,50 10,88 Smarty 7,50 10,00 8,25 9,00 11,38 6,00 8,69 Suzy 6,00 6,25 6,75 5,50 7,50 4,75 6,11 Mean 8,81 8,50 8,13 6,75 9,88 6,22 LSD 0,05 A - 3,94 B - 1,47. C - 0,80 A(B) - 3,98 B(A) - 3,75 A(C) - 2,79 C(A) - 1,59 Pinokkio 31,25 19,25 19,50 12,75 24,38 17,00 20,69 Popey 37,25 35,75 25,25 27,25 32,75 30,00 31,38 Smarty 33,25 22,50 23,00 11,00 27,88 17,00 22,44 Suzy 37,50 35.75 28,75 17,75 38,13 21,75 29,94 Mean 34,87 28,31 24,13 17,19 30,78 21,44 LSD 0,05 A - 6,60 B - 3,56 C - 1,26 A(B) - 7,38 B(A) - 7,12 A(C) - 4,60 C(A) - 2,52 390